Bait Fishing: Bait fishing is the most effective way to take a limit of trout here in the Bay Area. Here's my standard setup. I use a 6.5 foot ultralight rod loaded with 4 pound line. I thread on a 1/4 oz egg sinker and tie off to a #10 swivel. Then goes on 2-20 (sometimes 20 foot leader outfishes shorter ones 10:1) feet of 2 pound leader. I use a small #10 mustad light wire aberdeen hook. For bait I use a single miniature marshmallow (by Kraft, don't waste money on the ones for fishing) and a pea sized ball of chartreuse power bait.
Casting: My favorite lure (and everyone elses) is a Kastmaster. I prefer the 1/4 ounce gold model. Even the little stocker fish seem to like this larger version. However, I remove the factory treble and replace it with a barbless #6 gamakatsu round bend treble. My tackle for throwing this is a light action 6.5 foot rod with 4 lb P-line CXXX strong. This is a great strong line that allows good casting range, and disappears well underwater.
When the fish are up on top I will make a long cast and retrieve at a moderate to fast pace. Often they really want a fast retrieve. When the fish are deeper, mostly during the day, I let it sink to the bottom and retrieve slowly.
Flat-Line Trolling: Trolling can be extremely effective in the South bay in April and early May. I use one rod with my kastmaster on it, and the other with Seps mine flashers and a small orange bikini needle fish trailing behind. This is a killer combo at Loch Lomond. Try trolling fast.
Bay Area Hotspots for Trout: Loch Lomond Reservoir, Coyote Reservoir, Shadow Cliffs Reservoir, Lexington Reservoir, Stevens Creek Reservoir